This invention relates to padlocks and, more particularly, to combination padlocks constructed for use in high security and high resistance applications.
Numerous lock constructions have been developed and are widely employed by individuals to prevent unauthorized persons from gaining access to any area which has been closed and locked. Although many locks are constructed to be opened by a key, numerous combination locks have been developed which are opened by knowledge of a particular combination.
One particular type of combination lock that has become very popular, due to it ease and convenience of use, is a combination lock which employs a plurality of rotatable independent dials, each of which comprises a plurality of indicia, usually numbers or letters, which define the combination for releasing the lock. Although locks of this general nature had been available for several decades, these prior art combination lock constructions are typically employed in low security areas, due to their inability to resist forced entries in which excessive force is applied to the lock.
In those areas wherein a high security lock system is required, prior art constructions have relied upon padlocks which require a key for operating the lock between its alternate open position and closed position. Due to the ease with which keys are often lost or misplaced, as well as the proliferation of the keys required for many individuals to carry, high security padlocks requiring keys for operation has become increasingly unpopular. However, prior art constructions have been incapable of providing a high security padlock incorporating a combination system for operating the padlock.
In addition to prior art, high security padlock constructions relying upon key activation and operation, another problem which has consistently plagued prior art constructions is the cost of construction for producing and assembling prior art padlocks. In order to attain a padlock which provides all of the features desired by the users, prior art constructions typically incorporate numerous small components, each of which require inexpensive assembly procedures to produce the final product. As a result, these prior art high security padlock constructions are typically expensive to produce, thereby reducing the ability of these padlocks to reach a broader base of users.
Another problem commonly found with prior art high security padlocks is the inability of these prior art constructions to prevent contaminants from reaching the internal components of the padlock, thereby causing damage to these components and interfering with the ease of operation of the padlock by authorized personnel. Although numerous attempts have been made to reduce the adverse effect caused by contaminants reaching these components, such attempts have been incapable of satisfactorily eliminating this problem.
A further problem commonly found in prior art high security padlocks is the ability of these locks to be opened by unauthorized individuals using known picking techniques. In particular, since most prior art products employ keys for their operation, unauthorized entry is a common problem.
Therefore, it is a principal object of the present invention to provide a padlock construction which is specifically designed for effective operation in high security applications and is completely operable using a combination system.
Another object of the present invention is to provide a combination padlock construction having the characteristic features described above which virtually eliminates the ability of unauthorized persons from gaining access to the lock by attempting to pick the lock using known techniques.
Another object of the present invention is to provide a combination padlock construction having the characteristic features described above which employs a minimum of components and is quickly and easily assembled, thereby providing a lock capable of being constructed at a competitive price.
Another object to the present invention is to provide a combination padlock having the characteristic features described above which effectively seals the rotating components from external contamination and effectively prevents any external contaminants from reaching the rotating components and thereof.
Other and more specific object will in part be obvious and will in part appear hereinafter.
By employing the present invention, all of the difficulties and drawbacks of the prior art constructions are fully eliminated and an effective, easily produced, high security padlock is achieved which employs a combination system for fully operating the padlock. Furthermore, the high security, combination padlock of the present invention virtually eliminates the ability of unauthorized persons from opening the padlock using known picking techniques. In addition, the padlock construction of the present invention is designed with the interior chambers thereof virtually sealed from ambient surroundings, thereby preventing unwanted contamination from entering the interior of the lock and/or the rotating components thereof. In this way, the prior art degradation and interference of the lock operation by contamination is virtually eliminated.
In accordance with the present invention, a minimum number of components are employed in combination with a housing and an elongated movable locking bar or shackle in order to provide the desired, unique combination lock construction of this invention. By employing a minimum number of components in the construction of the high security, combination padlock of this invention, a highly efficient and cost effective product is realized.
In addition, the combination padlock of the present invention is constructed from heavy duty metal, such as brass, stainless steel, hardened steel, and the like, with an enlarged, heavy duty locking bar or shackle being employed for providing the desired securement. In addition to assuring that heavy duty, strong, tamper resistant materials are employed, the present invention also employs a tamper-proof holding cavity for the terminating, locking end of the locking bar.
One of the problems that has existed with prior art structures is the ability of unauthorized individuals, seeking to break open a prior art padlock, to be able to forcibly move the locking bar of these prior art padlocks by impacting upon a terminating end of the locking bar. In order to avoid any such possibility with the present invention, the heavy duty, metal based housing or body of the padlock is constructed for cooperating engagement with the terminating, locking end of the locking bar by incorporating an integrally formed receiving cavity within which the locking end is retained. As a result, any unauthorized individual is incapable of gaining access to the terminating, locking end of the locking bar since the terminating, locking end of the locking bar is securely retained within an integrally formed portion of the housing or body.
Another feature incorporated into the combination padlock of the present invention is a unique tumbler or clutch wheel construction which cooperates with the rotating dials to virtually eliminate any possibility that an unauthorized person would be capable of gaining access to the padlock by known combination lock picking techniques. In this unique construction, each tumbler or clutch wheel is constructed with a plurality of radially extending fins formed thereon, with each of the fins being arcuately spaced from the adjacent fin in a non-symmetrical pattern. This non-symmetrical spacing is most easily achieved by having each of the fins arcuately spaced from each adjacent fin by unequal radial distances.
As a result of this construction, in addition to being required to attempt to determine the correct position for each of the rotating dials, an unauthorized individual attempting to use known picking techniques would be required to align each tumbler or clutch wheel in a single correct position while hearing a plurality of xe2x80x9cclicksxe2x80x9d as each fin aligns with a receiving cavity formed in the housing, even when the other fins are not properly aligned. In this way, numerous false and mis-leading sounds are produced, causing any individual to be completely frustrated and unable to open the padlock of the present invention.
A further feature incorporated into the padlock of the present invention is a break-away handle or knob mounted to the activating slider shaft. In the preferred construction, the tumblers or clutch wheels and dials are mounted about a slider shaft which is axially movable only when the correct combination has been entered on the dials. In order to enable a user to operate the slider shaft, a handle or knob is mounted on one end of the slider shaft.
In normal use, the handle or knob is employed to axially move the slider shaft in order to unlock the shackle or locking bar. For this purpose, the handle/knob is secured to the slider shaft. However, if an unauthorized individual attempts to open the padlock by force and, in exerting this force, applies excessive pressure to the handle/kob in an attempt to forceably move the slider shaft, the break-away feature of the handle/knob causes the handle/knob to be separated from the slider shaft, leaving a slippery, no-grip metal end. Once separated, the handle/knob cannot be attached to the slider/shaft and the attempt to forceably open the padlock will have failed with no further means being available to the unauthorized person.
Another feature incorporated into the padlock of the present invention is a unique combination setting and re-setting assembly which also provides a positive stop mode when the combination re-setting position is not desired. In accordance with the present invention, the slider shaft incorporates a radially extending post which must pass through a key-hole slot formed in the body or housing of the padlock for activating the combination setting or re-setting mode.
In addition, a set-screw member is threadedly engaged with the housing or body of the padlock positioned between the normal, operating position of the radial post and the key-hole slot. As a result, axial movement of the slider shaft during normal operation causes the post to contact the set screw when aligned therewith, thereby preventing accidental entry into the combination setting/resetting mode.
Whenever the user wishes to set or re-set the combination, the set screw must be partially withdrawn from the housing or body in order to enable the radial post to pass the set screw and enter the keyhole slot. In this way, accidental movement of the slider shaft into the set/re-set mode is eliminated and users are assured that only intentionally entered combinations will open the padlock.
The invention accordingly comprises an article of manufacture possessing the features, properties, and the relations of elements which are exemplified in the article described herein and the scope of the invention will be indicated in the claims.